I think the following specific sound should be improved:
1. "vacuum cleaners" exhaust as everyone has mentioned should be replaced with more realistic sound.
2. The intake sound, upon upgrade, should sound meaner than standard.
3. Engine, intake, exhaust sound should be recorded separately from at least 2 sources. Not the same one sound source like in the current game.
Regarding #2, and #3, I actually drive a Lexus IS350 with both FSport intake and exhaust add on (hence my screenname FSport IS
). The exhaust starts to growl from 2500 RPM to 3500 with a low vrrooom sound and @3500 + it growls with higher pitch. The intake only kicks in @3500 RPM or higher. I'm not saying all cars have to follow this pattern. Each car has its unique pattern with the sound varying at different RPM. It would be awesome if they capture this.
watch this
www.youtube.com/watch?v=tpn8PTyNgj4
4. Sound of car bumping into each other is like two wooden boxes hitting each other. It should be metal crashing sound.
5. The tire squeak sound is too simplistic. 3a-the volume of the sound that should be adjusted depending on the condition of the available traction so it actually varies in different time and not flat level like in game. 3b-Different tires compounds gives out different warning sound when push to the limit.
6. Brake does squeak sometimes in real car which is not modeled in game. If they can add this in, that is a plus.
7. When real cars go over bump, you might hear squeak from the windows or body frame especially when the car is getting old. If they can add this in, that is a plus.
I will have to gives props to PD for modeling the sound with consideration of the distance. If you notice, depending on different views (interior, chase etc), the sound is reflected differently. It is not perfect but quite good enough.
I have a Master degree in engineering but not specifically sound engineering. I would volunteer to help them on a short term project for free if I specialize in sound. Anyways, I hope the sound engineers would take some of my points above into consideration.